1. Field of the Invention
This disclosure relates to an image forming apparatus such as a copier, a printer, a facsimile, and a multifunction printer having a plurality of their functions.
2. Description of the Related Art
An intermediate transfer-type image forming apparatus which transfers a toner image formed on a photosensitive drum to an intermediate transfer belt and conveys the toner image to a transfer portion which transfers the toner image to a recording medium has been widely used. For example, JP-A-2007-57803 discloses an intermediate transfer-type image forming apparatus configured to clean an intermediate transfer belt by using an electrostatic cleaning-type belt cleaning unit.
By the way, the intermediate transfer belt is inclined to be attached with transfer residual toner charged with a polarity reverse to a toner charging polarity after transferring a toner image on a recording medium. Due to that, JP-A-2007-57803 collects the toner in an electrostatic manner from the intermediate transfer belt by abutting a second brush roller to which voltage of a polarity reverse to the toner charge polarity is applied with the intermediate transfer belt downstream of a first brush roller to which voltage of a same polarity with the toner charge polarity is applied.
A transfer belt-type image forming apparatus transferring a toner image borne on a photosensitive drum or the like to a recording medium carried on a transfer is also widely used. JP-A-2006-259367 discloses a transfer belt-type image forming apparatus configured to clean a transfer belt by using an electrostatic cleaning-type belt cleaning unit.
There is a case when the transfer belt is adhered with the toner charged with a polarity reverse to the charge polarity of the toner transferred from a patch toner image formed between images consecutively formed after separating the recording medium on which the toner image has been transferred. Due to that, JP-A-2006-259367 recovers the toner in an electrostatic manner from the secondary transfer belt by abutting a second brush roller to which voltage of a same polarity with the toner charge polarity is applied with the secondary transfer belt downstream of a first brush roller to which voltage of a polarity reverse to the toner charge polarity is applied.
It is desirable to be able to recover the toner more efficiently from the endless belt such as the intermediate transfer belt and the transfer belt with the configuration including the first and second brush rollers as described above.